12. March 2015

Around the Corner Balcony

from Alexander Krenczik


Condominiums and apartment buildings can be designed with corner, wrap around balconies to provide dramatic views. These corner balconies are most commonly cantilevered concrete balconies which are a slab extension from the building’s interior slab surface.

Corner balconies provide heightened aesthetics designs as well as ensure optimal sun exposure on the balcony. This is especially important when your balcony faces east, to allow a corner section on the south to provide additional sun exposure during the day. In dormitories, balconies are often used as loggia walkways around the building as an evacuation scenario for a fast and secure escape.

Building with Wrap around Corner Balconies.
Building with Wrap around Corner Balconies.

Structural Connections with Performance

Since thermal bridging is a common issue in continuous concrete slabs, a thermal break should be integrated into the design. Thermally separating the interior concrete slab from the exterior corner balconies requires structural considerations.

First of all, there is only a small corner to anchor the force from the corner segment back to the structure (blue square), and secondly the corner has geometrically the furthest projection (yellow line).

Top view of corner balcony


Top view of corner balcony.

 Solution for Corner Balconies

Schöck Isokorb® has developed a special structural element to anchor the forces occurring at the corner back to the slab structure while additionally providing a thermal break.


Schock Isokorb type K-corner consists of two partial units, 1st layer and 2nd layer.
Schock Isokorb type K-corner consists of two partial units, 1st layer and 2nd layer.


Slab Balcony thickness

The corner elements consist of two separate “legs” for the corner with thicker rebar diameter and different layers of reinforcement, so that the bars cross over each other. The Schöck Isokorb® corner installation is an efficient quick and simplistic solution to provide thermally efficient corner balconies.

There are 3 different standard structural thermal break product types available for different load ranges, depending on the cantilever length. Additional customized thermal break solutions can be designed to suit project needs and load conditions.

Here is an example:

Balcony corner with Isokorb thermal breaks
Balcony corner layout with Isokorb thermal breaks.
Balcony corner with Isokorb structural thermal break
Balcony corner with placement of Isokorb structural thermal breaks.


The Engineering team at Schöck will design the most suitable and economical solution for your project with PE stamp and seal in the project’s jurisdiction.


Conclusion: An engineered solution is available to structurally connect corner balconies and provide a thermal break, improving energy performance at the balcony while continuing around the corner.


Visit the Schöck North America website for more information about structural thermal breaks for concrete and steel connections. Explore the full range of Isokorb® products for balcony, canopy, steel beam, exposed slab edge, parapet and rooftop connections.

Considering structural thermal breaks for an upcoming project? Have a Schöck Engineer call you to answer your specific design questions.  


05. October 2016 um 17:37

Hi, I have a question concerning the connections of balconies
enclosed by three walls, a balcony in particular which will extend
further than the walls of the building itself, for lack of a better
phrase, protruding proud of the building; say I use thermal break
such as Schock Isokorb type CM on the two opposite walls (as they
are the loadbearing walls) and the balcony itself will need to be
prefabricated using lightweight concrete construction. How then
would I place it into this three walled corner with the rebar of
both Schock CM’s sticking out? I cannot think of a feasible
solution to this issue. I would appreciate feedback. Thank you

Tracy Dacko
07. October 2016 um 11:35

Hi, thanks for your comment and interest in thermal break solutions for corner balconies. The question seems more related to pre-cast balconies than corners. Schöck Isokorb® systems can accommodate precast balconies, but the solution will depend on whether the entire structure is pre-cast or if only pre-cast balconies are being attached onto a cast-in-place structure. You have described a balcony slightly inset into the building with three adjacent walls that projects beyond the building facade. The supporting system (Isokorb CM, CV, or CMD) will depend on if the two opposite structural walls are used as described, or if a single middle wall is used alternatively.

If the building structure is cast-in-place and the balcony pre-cast, the Isokorb can be built into the balcony then tied into the slab rebar before the slab is poured. If both the balcony and the building are pre-cast separately, or if the building must be built first and balcony attached later, we have a system called iDock for this. iDock is a plastic mould that must be built into the slab. The mould allows space for the balcony rebar ends to fit into the slab. Once the connection has been made, the bars can be grouted into the slab to fill the mould and level off the top of the slab. The balcony would have to be supported with temporary shoring until the grout has hardened the connection into the slab.

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